Implement wordWrap and paginate

test/spec/HCatSpec.hs

@@ -1,12 +1,12 @@
--- {-# LANGUAGE GHC2021 #-}
-
 module HCatSpec (spec) where
 
-import HCat.Internal (chunksOf, parseArgs)
+import HCat.Internal
 
 import Test.Hspec
 import Test.Hspec.QuickCheck (prop)
-import Test.QuickCheck (Positive (getPositive))
+
+import Test.QuickCheck (Positive (getPositive), getNonPositive)
+import Test.QuickCheck.Instances.Text ()
 
 spec :: Spec
 spec = do
@@ -15,6 +15,7 @@ spec = do
       parseArgs ["foo"] `shouldBe` Right "foo"
       parseArgs [] `shouldBe` Left "No filename given!"
       parseArgs ["foo", "bar"] `shouldBe` Left "Only a single file is supported"
+
   describe "chunksOf" $ do
     prop "each chunk contains at most N items" $ \n xs ->
       let chunkLengths = length <$> chunksOf n (xs :: [Int])
@@ -25,3 +26,19 @@ spec = do
     prop "the sum of all lengths is equal to the length of the input" $ \n xs ->
       let chunkLengths = length <$> chunksOf (getPositive n) (xs :: [Int])
        in sum chunkLengths `shouldBe` length xs
+
+  describe "wordWrap" do
+    prop "non positive margins result in empty result" $ \margin ->
+      wordWrap (getNonPositive margin) "abc" `shouldBe` ["abc"]
+
+    it "wraps the given text at the given margin" do
+      wordWrap 4 "abc" `shouldBe` ["abc"]
+      wordWrap 4 "abcdefg" `shouldBe` ["abcd", "efg"]
+
+    prop "concatenating the result equals the input" $ \txt ->
+      let wrapped = wordWrap 4 txt
+       in mconcat wrapped `shouldBe` txt
+
+  describe "paginate" do
+    it "wraps the given text at the given margin" do
+      paginate (ScreenDimensions 3 2) "abcdefghijkl" `shouldBe` ["ab\ncd\nef\n", "gh\nij\nkl\n"]